Organically-modified porous silicates have been prepared according to a one-pot synthetic approach. A mixture of phenyltriethoxysilane and tetraethoxysilane was reacted with an acidic solution of cetyltrimethylammonium bromide (CTAB). Depending on the preparation conditions, not only the hexagonal (2d, p6m) but also a cubic phase has been prepared analogous to the already reported SBA-1 phase, whose X-ray pattern matches the (Pm3n) space group. To our knowledge, it is the first time that this phase is obtained with CTAB as structuring agent, which suggests specific interactions between the phenyl groups and the surfactant polar head group. The surfactant was removed by solvent extraction or calcination at 350°C, without any alteration of the ordering: a cubic porous silicate network functionnalized by phenyl groups was thus obtained. Calcination could even be performed at 600°C to prepare a pure silicate network that still exhibits the same cubic symmetry.

A one-step, fast, and potential low cost process has been developed to fabricate silicalike glass nanostructures by combining sol-gel chemistry and thermal nanoimprint. An inorganic-organic sol-gel thin film is patterned at low pressure and temperature with flexible stamps. Various geometries are achieved with a patterning resolution of about 150nm and pattern aspect ratio higher than 4. To obtain pure silica structures a thermal annealing at high temperatures is required. During this step most of the structures collapse due to fluidization of the sol-gel material. It is shown that if a suitable condensation level is obtained during imprinting, the nanostructures are thermally stable.

The formation of mesoscopically ordered silica/surfactant composites under acidic synthesis conditions is studied by time-resolved in-situ small-angle X-ray scattering (SAXS) using synchrotron radiation. Benzene is used a an additive which acts as a weak swelling agent although most of the benzene molecules are found to reside near the surfactant/silicate interface region rather than in the micelle cores. With increasing relative amounts of benzene, the curvature of the micellar aggregates decreases, which finally leads to a transition from (hexagonally) rodlike to lamellar; a mechanism for this change in curvature is suggested.